Pedestal type scaffolds, as exemplified in the above patents, typically have an upright mast mounted on a relatively small base member, and a work cage mounted on the mast for vertical movement. The base member is provided with two sets of caster wheels to enable the scaffold to be rolled horizontally while the mast is in its vertical work position.
This type scaffold is also typically provided with a transport set of caster wheels which enables the scaffold unit to be tilted over so that it is supported on the transport set and on one of the two sets of base casters, with the mast being substantially inclined from vertical. In this mode, the overall height of the pedestal scaffold is considerably reduced so that it can easily pass through areas of low overhead clearance, such as doorways. Also, the wheelbase defined by the transport set and one base set of caster wheels is considerably greater than the wheelbase of the two base sets of caster wheels so that the scaffold unit is much more stable when it is in the transport mode.
Pedestal scaffolds as described above have a drawback in that when the scaffold is tilted over from its upright working position to its transport position, the workman must himself support a considerable amount of weight after the scaffold has been tipped over and until the transport casters touch the floor or ground. The greater the final inclination from vertical of the mast when in the transport position, and the greater the wheelbase when in transport position, the greater the weight that the workman will have to support.
Additionally, pedestal scaffolds are relatively difficult to move from one horizontal level to another, such as from the ground to a loading dock or to a truck bed. This difficulty is increased when the scaffold unit is fully self contained, with its own hydraulic system, electrically driven pumps and storage batteries. In such case the scaffold unit may weigh in the order of 600 pounds, requiring a number of workmen, or special equipment, to load or unload the scaffold from a truck.